MCQ Detailed View

The lanthanides, also known as rare earth elements, consist of the 14 elements from cerium (Ce) to lutetium (Lu). These elements are f-block elements with electrons filling the 4f orbitals.

The common oxidation state of lanthanides is +3. This is because the removal of the two 6s electrons and one 5d or 4f electron results in a stable electronic configuration, leaving the 4f orbitals partially filled. The +3 oxidation state is observed in almost all lanthanide compounds, including oxides, halides, and sulfates.

Some lanthanides exhibit other oxidation states:

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  +2: Observed in Eu²⁺ and Yb²⁺ due to the stability of half-filled (Eu) or filled (Yb) 4f orbitals.

  
  


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  +4: Rare, seen in Ce⁴⁺ in cerium dioxide (CeO₂) due to stabilization of the 4f⁰ configuration.

  
  

The +3 state is most stable due to a combination of ionization energy trends and 4f orbital shielding. The stability of the +3 state explains why it dominates in chemical reactions, coordination compounds, and industrial applications such as in magnets, phosphors, and catalysts.

Understanding the common oxidation state is crucial for predicting the reactivity, compound formation, and electronic configuration of lanthanides. Since the 4f orbitals are well shielded by 5s and 5p orbitals, the chemistry of these elements is largely dominated by ionic interactions and +3 oxidation state compounds.

Thus, in summary, the common oxidation state of lanthanides is +3, with minor variations in a few elements under specific conditions.